Structural and spectroscopic studies of transition metal nitrite complexes. V. Crystal structures and spectra of trans-Tetrakis(pyridine)dinitritonickel(II)-pyridine (1/2), trans-Tetrakis(4-methylpyridine)dinitritonickel(II) and trans-Tetrakis(pyrazole)-dinitritonickel(II)

1981 ◽  
Vol 34 (10) ◽  
pp. 2095 ◽  
Author(s):  
AJ Finney ◽  
MA Hitchman ◽  
CL Raston ◽  
GL Rowbottom ◽  
BW Skelton ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Transition Metal ◽  
Crystal Structures ◽  
Electronic Spectra ◽  
Spectroscopic Studies ◽  
Molecular Structures ◽  
Aromatic Rings ◽  
Paddle Wheel ◽  
Crystal And Molecular Structures ◽  
Infrared Frequencies

The crystal and molecular structures of the compounds [Ni(py)4(ONO)2],2py, [Ni(γmpy),(ONO)2] and [Ni(prz)4(ONO)2] are reported.�All three are trans nitrito complexes, the pyridine (py) compound containing two pyridine molecules of solvation. The aromatic rings in the first two complexes adopt 'paddle wheel' conformations with pitch angles varying between 40 and 70�. The nitrite ions are positioned so as to minimize repulsive interactions with the amines, and it seems likely that these groups bond through oxygen rather than nitrogen because this allows a lesser degree of interligand steric interference. The amine rings in [Ni(prz)4(ONO)2] are orthogonal to the plane containing the nickel and coordinated pyrazole nitrogen atoms; the nitrito groups are disordered between two inequivalent positions, each of which involves hydrogen bonding with the pyrazole NH groups. The nitrite infrared frequencies are similar to those observed for other nickel(II) nitrito complexes except that the antisymmetric NO stretching mode of one of the groups in the pyrazole complex is much lower in energy than expected, being in the range normally associated with a nitrogen-bonded or chelated nitrite group. It is suggested that this deviation may be caused by the hydrogen bonding in the complex. The electronic spectra of the compounds yield 10Dq values of 9100 and 8500 cm-1 for the nitrite ligands in [Ni(py)4(ONO)2] and Ni(prz)4(ONO)2], respectively, placing the nitrito group towards the weaker end of the spectro-chemical series.

Structural and spectroscopic studies of transition metal nitrite complexes. VIII. Crystal structures and spectra of three pentanuclear species with stoichiometry [Ni5(N-substituted ethane-1,2-diamine)4(OH)2(NO2)8]

1981 ◽  
Vol 34 (10) ◽  
pp. 2139 ◽  
Author(s):  
AJ Finney ◽  
MA Hitchman ◽  
CL Raston ◽  
GL Rowbottom ◽  
AH White
Keyword(s):  
Transition Metal ◽  
Crystal Structures ◽  
General Formula ◽  
Infrared Spectra ◽  
Spectroscopic Studies ◽  
Molecular Structures ◽  
Structural Variations ◽  
Crystal And Molecular Structures

The preparation of a series of novel compounds of general formula [Ni5L4(NO2)8(OH)2] formed by ethane-1,2-diamine or one of five N-substituted ethane-1,2-diamines (L) is described. The crystal and molecular structures of the ethane-1,2-diamine, N,N'-diethylethane-1,2-diamine and N,N-dimethylethane-1,2-diamine complexes are reported. Each compound contains a planar, pentameric arrangement of nickel(II) ions, linked by bridging hydroxide and nitrite ligands. The details of the nitrite bridges differ among the complexes, causing differences in their electronic and infrared spectra. The structural variations are probably caused by the differing steric requirements of the amine substituents.

The Nature of the Hexahydrates of Divalent Transition Metal Cations: The Structures of the Hexafluorogermanate Hexahydrates of Iron(II), Cobalt(II) and Nickel(II)

1987 ◽  
Vol 40 (3) ◽  
pp. 565 ◽  
Author(s):  
BF Hoskins ◽  
A Linden
Keyword(s):  
Hydrogen Bonding ◽  
Transition Metal ◽  
Room Temperature ◽  
Unit Cell ◽  
Molecular Structures ◽  
Symmetry Element ◽  
Mirror Plane ◽  
Crystal And Molecular Structures ◽  
Cscl Type ◽  
Rhombohedral Symmetry

The crystal and molecular structures of the room temperature phases of MII(H2O)6GeF6 (M = Fe, Co, Ni) are reported. In each structure the M(H2O62+ and GeF62- octahedra are in approximate CsCl -type packing with hydrogen bonding between the ions. Differences in the structures arise from disorder in the orientations of the octahedra . Fe(H2O)6GeF6 crystallizes in the spate group R3M, with three molecules in the unit cell of dimensions ahex , 9.728(2), Chex 9.796(2) �. Refinement converged with R 0.0135 and Rw 0.0137, 286 independent observed reflections being used. There is disorder of both fluorine and oxygen atoms between two positions related by a mirror plane, which raises the 3 symmetry within each octahedron to overall 3m symmetry. Ni(H2O)6GeF6 crystallizes in the spate group R3 with three molecules in the unit cell of dimensions ahex 9.443(1), chex 9 .77O(l) �. Refinement converged with R 0.016 and R, 0.018 for 444 independent observed reflections. There is disorder only of the fluorine atoms between two positions unrelated by any symmetry element. CO(H2O)6GeF6 crystallizes in the space group P21/c with two molecules in the unit cell of dimensions a 6.552(2), b 9.577(2), c 8.520(1) �, ,β 99.74(2)�. Refinement converged with R 0.042 and R, 0.054 for 1232 independent observed reflections. The structure is not disordered and deviates only slightly from rhombohedral symmetry.

Structural and spectroscopic studies of transition metal nitrite complexes. III. Crystal structures and spectra of Aquabis(meso-1,2-diphenylethane-1,2-diamine)-nitronickel(II) perchlorate and Bis(meso-1,2-diphenylethane-1,2-diamine)-(nitrito-O,O')nickel(II) chloride

1981 ◽  
Vol 34 (10) ◽  
pp. 2069 ◽  
Author(s):  
AJ Finney ◽  
MA Hitchman ◽  
CL Raston ◽  
GL Rowbottom ◽  
AH White
Keyword(s):  
Fine Structure ◽  
Water Molecule ◽  
Single Crystals ◽  
Electronic Spectra ◽  
Spectroscopic Studies ◽  
Molecular Structures ◽  
Nitrite Ion ◽  
Nickel Ion ◽  
Crystal And Molecular Structures ◽  
Coordinated Water

The crystal and molecular structures of the complexes [Ni(mstien),(NO2)(H2O)] ClO4 and [Ni(mstien)2(O2N)] Cl are reported (mstien = meso-stilbenediamine, 1,2-diphenylethane-1,2-di-amine). Both compounds contain nickel(II) in an essentially octahedral ligand environment. In the latter complex, the nitrite ion chelates, while in the former it is present as a nitro group situated trans to a coordinated water molecule. In both complexes the conformations observed for the amine chelate rings can be rationalized on the basis that they minimize intramolecular ligand repulsions. The complex [Ni(mstien)2(O2N)] NO2 is isomorphous with the analogous chloride compound, and spectral evidence suggests that the complex [Ni(mstien)2(O2N)] ClO4 also contains a chelating nitrite group. The electronic spectra of single crystals of [Ni(mstien),(O2N)] X (X = Cl- and NO2-) show bands centred at c. 25000 cm-l which exhibit vibrational fine structure. The energies of the progressional spacings are c.600cm-l, which suggests that the bands are probably due to n → π* internal nitrite transitions. The band centred at c. 20500 cm-1 in [Ni(mstien)2(NO2)(H2O)] ClO4 also shows well resolved vibrational fine structure with a progressional spacing of c. 630 cm-1. This implies that the band is not due to a 'd-d' transition, but must be caused by the excitation of an electron into the nitrite π* orbital, either from a non-bonding nitrite orbital, or more probably from the nickel ion.

Crystal structures of dihydroquercetin 3-acetate and dihydroquercetin 3,3'4',7-tetraacetate: hydrogen bonding in 5-hydroxyflavanones

1999 ◽  
Vol 77 (8) ◽  
pp. 1436-1443 ◽  
Author(s):  
Eberhard Kiehlmann ◽  
Kumar Biradha ◽  
Konstantin V Domasevitch ◽  
Michael J Zaworotko
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Single Crystal ◽  
Crystal Structures ◽  
Crystal Packing ◽  
Heterocyclic Ring ◽  
Molecular Structures ◽  
Crystal Data ◽  
Aromatic Rings ◽  
X Ray

The molecular structures of dihydroquercetin 3-acetate 3 and dihydroquercetin 3,3',4',7-tetraacetate 4 were determined by single crystal X-ray analysis. Comparison of their crystal data with those of 16 known 5-hydroxyflavanones shows intramolecular O(5)-H···O(4)=C hydrogen bonding, preference for nearly perpendicular orientation of the two aromatic rings and preferred sofa conformation of the heterocyclic ring. The major stabilizing force in the crystal packing pattern of 3 is intermolecular hydrogen bonding.Key words: crystal structure, dihydroquercetin, flavanones, hydrogen bonding.

Lewis-Base Adducts of Group 1B Metal(I) Compounds. XXI The Crystal and Molecular Structures of the Unsolvated Forms of Dibromotris(triphenylphosphine)dicopper(I) and 'step' Tetrabromotetrakis(triphenyl-phosphine)tetracopper(I)

1985 ◽  
Vol 38 (8) ◽  
pp. 1243 ◽  
Author(s):  
JC Dyason ◽  
LM Engelhardt ◽  
C Pakawatchai ◽  
PC Healy ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Molecular Structures ◽  
Lewis Base ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
Triphenyl Phosphine ◽  
X Ray ◽  
Crystal And Molecular Structures

The crystal structures of the title compounds have been determined by single-crystal X-ray diffraction methods at 295 K. Crystal data for (PPh3)2CuBr2Cu(PPh3) (1) show that the crystals are iso-morphous with the previously studied chloro analogue, being monoclinic, P21/c, a 19.390(8), b 9.912(5), c 26.979(9) Ǻ, β 112,33(3)°; R 0.043 for No 3444. Cu( trigonal )- P;Br respectively are 2.191(3); 2.409(2), 2.364(2) Ǻ. Cu(tetrahedral)- P;Br respectively are 2.241(3), 2.249(3); 2.550(2), 2.571(2) Ǻ. Crystals of 'step' [PPh3CuBr]4 (2) are isomorphous with the solvated bromo and unsolvated iodo analogues, being monoclinic, C2/c, a 25.687(10), b 16.084(7), c 17.815(9) Ǻ, β 110.92(3)°; R 0.072 for No 3055. Cu( trigonal )- P;Br respectively are 2.206(5); 2.371(3), 2.427(2) Ǻ. Cu(tetrahedral)- P;Br are 2.207(4); 2.446(2), 2.676(3), 2.515(3) Ǻ.

Experimental and computational structural study of two hindered aminoanthraquinones in crystals and solutions

2000 ◽  
Vol 215 (9) ◽  
Author(s):  
A.V. Yatsenko ◽  
K.A. Paseshnichenko ◽  
S.I. Popov
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Electronic Spectra ◽  
Molecular Structures ◽  
Amino Group ◽  
Single Crystal Diffraction ◽  
Molecular Conformations ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Visible Spectra

The crystal and molecular structures of 2-methyl-1-methylamino-anthraquinone (I) and 1-methylphenylamino-anthraquinone (II) were studied by the X-ray single-crystal diffraction and the visible spectra of crystalline specimens and their solutions were recorded. The molecule I is closely planar, whereas in the molecule II the amino group is 58° rotated out of the plane of the anthraquinone skeleton. In both structures the molecules pack in stacks. The comparison of experimental and calculated (on the DFT and AM1 levels) molecular structures, together with the comparison of experimental and INDO/S-calculated electronic spectra, give the evidence that molecular conformations (especially for II) change upon transfer from the solid state to solutions, and the π-delocalisation throughout the whole molecule enhances in the solid state.

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